Field of the Invention
The present invention relates to a haptic operating device having a magnetorheological transmission apparatus and, in particular, a magnetorheological force or torque transmission apparatus, the transmission between a first component and at least one second component which is stationary or moves relative to the first component being able to be changed by the magnetorheological properties of a fluid between the components. The haptic operating device according to the invention can be used in various technical fields, for example for operating technical equipment such as vehicles or industrial installations or for operating washing machines, kitchen appliances, radios, hi-fi systems or other devices.
Magnetorheological fluids have very fine ferromagnetic particles, for example carbonyl iron powder, distributed in an oil, for example. Spherical particles having a production-related diameter of 1 to 10 micrometers are used in magnetorheological fluids, in which case the particle size is not uniform. If a magnetic field is applied to such a magnetorheological fluid, the carbonyl iron particles of the magnetorheological fluid are concatenated along the magnetic field lines, with the result that the rheological properties of the magnetorheological fluid (MRF) are considerably influenced depending on the form and strength of the magnetic field.
WO 2012/034697 A1 has disclosed a magnetorheological transmission apparatus having two components which can be coupled and the coupling intensity of which can be influenced. In order to influence the coupling intensity, a channel containing a magnetorheological medium is provided. The magnetorheological medium in the channel is influenced via a magnetic field. Rotating bodies, on which acute-angled regions containing the magnetorheological medium are provided, are provided in the channel. The magnetic field from the magnetic field generation device can be applied to the channel or at least one part of the latter in order to selectively concatenate the particles and to wedge them with the rotating body or release them. This magnetorheological transmission apparatus can also be used on a rotary knob for operating technical devices. Such a magnetorheological transmission apparatus functions and allows very high forces or torques to be transmitted with a simultaneously relatively small design.
EP 1 168 622 A2 has disclosed, in FIG. 1, an electronically controlled fluid-filled rotary knob as a haptic operating element, a thin shearing gap which is filled with magnetorheological fluid being provided between a rotationally fixed soft magnetic yoke ring and a likewise rotationally fixed soft magnetic ring. A thin-walled and rotatable adjusting wheel is arranged in the shearing gap. A corresponding braking torque acts on the basis of a magnetic field acting on the shearing gap. The disadvantage of this is the extremely extensive thin shearing gap which surrounds the stationary outer soft magnetic ring on the outside and inside, with the result that the base friction is very high on account of the included fluid (magnetorheological fluid=viscosity similar to honey). In addition, the adjusting wheel is predefined by the shape of the rotationally fixed soft magnetic ring which is part of the magnetic circuit. As a result, the adjusting wheel cannot be produced from any desired materials. FIG. 2 of EP 1 168 622 A2 discloses another exemplary embodiment in which the adjusting wheel is used as return iron and is a rotatable part of the magnetic circuit. The adjusting wheel completely surrounds a stationary arrangement of a yoke iron, coils and a plurality of yoke rings. The magnetic field runs radially through the shearing gap. The disadvantage is the thin shearing gap which is likewise very extensive and is practically as large as the inner surface of the adjusting wheel. In addition, the adjusting wheel is part of the magnetic circuit and can therefore be produced only from particular materials having required magnetic properties. FIG. 3 of EP 1 168 622 A2 discloses another exemplary embodiment having a rotating actuator and a laminated stator part which consists of soft magnetic material, has an armature winding and produces a radially running magnetic field in a magnetically active gap between a radially inner stator part and a radially outer stator part. Both stator parts are connected to one another and consist of a soft magnetic material. The gap contains an annular and non-magnetic rotor which is connected to a bell-shaped operating body via a shaft. The gap also contains a magnetorheological fluid. Around the shaft, the rotor has a bell-shaped rotor body, the annular wall of which engages in the gap between the radially inner stator part and the radially outer stator part. In this exemplary embodiment as well, the shearing area between the rotor body and the stator parts is very large, thus producing a very high base torque. Operation using a finger is not possible in daily operation. Therefore, a haptic operating element according to EP 1 168 622 A2 is not suitable for use as a sensitive haptic operating element.
It has been found during many tests that a haptic operating element can be used commercially as a standard product for infotainment in automobiles, for rotating actuators on smart devices or as an actuator on devices (for example: oscilloscope), for example, virtually only when the base torque (idling torque with the magnetic field switched off; off-state torque) is less than 0.1 Newton meters (Nm). This applies to typical rotary knob diameters of 30, 40 or 50 mm. If a particularly small rotary knob diameter (for example<5 or 10 mm) is used, a base torque considerably lower than 0.1 Nm is very advantageous and necessary.
A base torque of less than 0.1 Nm cannot be easily achieved in a standard product with a magnetorheological basis. Brakes or clutches with magnetorheological fluid (MRF) can be used in steer-by-wire (large steering wheel or large force introduction distance) or to brake operations in machines. In commercially available products, the base torque is 0.4 to 0.6 Nm, that is to say a factor of 10 to 40 above the prior art of purely mechanical rotating actuators. The maximum torque of these units is between 5 and 12 Nm. The important factor between the base torque and the maximum torque (operating range factor) is therefore in the range of 12 to 20 in the prior art. Therefore, no MRF operating knob according to the MRF shearing principle has hitherto been implemented as a standard part in automobiles.
Haptic operating elements, in particular rotating actuators in vehicles or on smart devices, require, for standard use which is accepted by the user, a base torque which is many times smaller than in the prior art (MRF brakes according to the shearing principle); these base torques are below 0.2 Nm and better less than 0.1 Nm and ideally below 0.05 Nm. Fingers are very sensitive here. For comparison, the haptic operating range (a fine latching pattern) of a known and purely mechanical rotating actuator (benchmark in automobiles) having a knob diameter of approximately 50 mm is between approximately 0.01 Nm (base torque) and a maximum torque of 0.05 Nm (peak ripple). A conventional infotainment rotary knob in the center console (rotating actuator with a rotary knob diameter of 50 mm, for example) with a base torque of 0.06 Nm is not accepted by many automobile manufacturers (cannot be commercially implemented). The necessary blocking (at least 5 Nm, for example simulation of an end stop or the position “P” in the gear selector switch) must then be produced using an additional locking pin (electrically actuated lifting magnet), for example.
A preferred object is therefore to provide an adaptive operating element, the braking torque of which can preferably be set between 0.02 Nm (or less) and 5 Nm (=operating range) in the millisecond range. A factor in the region of 250 between the base torque and the maximum torque is therefore required, which is more than 12 times more than that in the prior art.
In the automotive industry in particular, the intention is to reduce the number of operating knobs in the vehicle since the number has greatly increased on account of the multiplicity of functions. The aim is to substantially display only the currently required information and switching options. On the other hand, the customer should not have to enter and browse the menus too much in order to be able to carry out necessary functions. Therefore, the user must often be able to operate a haptic operating element without the use of force.
The aim of the invention is therefore to improve the advantageous variability and flexibility of haptic operating devices based on magnetorheological media in such a manner that they can be used for sophisticated haptic operating elements.
The intention is to provide a haptic operating device having a magnetorheological transmission apparatus, thus enabling even more flexible use.
A haptic operating device according to the invention is equipped with a basic body and a rotating unit, connected in particular to a shaft, and a magnetorheological transmission apparatus with at least two components which can be coupled. The coupling intensity of the two couplable components can be influenced. A magnetorheological medium which can be influenced by a magnetic field and has magnetically polarizable particles is arranged between the couplable components for the purpose of influencing the coupling intensities. At least one magnetic field generation device preferably having at least one electrical coil for generating at least one magnetic field is provided in order to influence the magnetorheological medium using the magnetic field. The magnetic field generation device is designed and set up to influence the magnetorheological medium using its magnetic field. The basic body is coupled to one of the two components and the rotating unit is coupled to the other of the two components. At least one rotatable transmission element is arranged in the channel as a magnetic field concentrator and is caused to rotate during a rotational movement of at least one of the components which can be coupled. The rotatable transmission element can be referred to as a rotating body or a magnetic field concentrator.
The magnetic field concentrator concentrates the magnetic field onto a smaller area. The transmission element may be in the form of a ball or roller, for example, without being restricted to these forms, and concentrates the magnetic field, that is to say the magnetic field is changed between the two components which are moved relative to one another and is concentrated from a large area onto a small area (a transition area). The ratio of these areas is considerably greater than 1 and, in particular, greater than 2, greater than 5 or, in particular, greater than 10. In principle, this is the ratio of the cylindrical area of the inner ring in relation to (the region of) the tangent edge of a roller or in relation to a ball point multiplied by a number of the transmission elements, in particular 15, for example.
The transmission element concentrates the magnetic field and forms a magnetic field or flux density concentrator.
The transmission element is connected neither to the first component nor to the second component in a rotationally fixed manner. The field concentrator can move “arbitrarily” between the two components.
Such a haptic operating device according to the invention has many advantages. The haptic operating device allows a very small base torque, thus making it possible to easily rotate the rotating unit or a rotary knob formed on the haptic operating device. An operator can conveniently rotate the rotating part using his little finger. A base torque which is less than 0.1 Nm and, in particular, less than 0.07 Nm and preferably less than 0.05 Nm is enabled, thus enabling convenient operation in daily use even if used frequently. It is not necessary to grip the rotating part using the entire hand or at least two fingers in order to rotate the rotating part (even repeatedly in succession). Simple touching and rotating using only one finger also generally suffice.
At the same time, a simple structure is enabled and only few parts are used. As a result of the simple structure, in which torque is transmitted through the magnetorheological medium or magnetorheological fluid (MRF) only inside the channel at least to the greatest extent, a particularly low base torque (base torque=torque needed for rotation when the electrical coil is switched off) can be achieved.
In contrast, a haptic operating element according to EP 1 168 622 A2 has the disadvantage that the base torque is very high because a very large amount of shearing area is used. The ratio of active area to useful area (shearing area) is very unfavorable. The shearing gap must be small for technological reasons, which in turn greatly increases the friction (fluid friction). The active shearing gap filled with MRF is very large.
In the present invention, the channel has a large radial extent (channel height), with the result that the base friction caused by the MRF per se, when the magnetic field is switched off or is low, is very low on account of the large radial extent. The large radial extent results in a large channel area. In contrast to this, however, the transmission/contact areas are very small. Only transmission elements (for example rollers) affect the moving and stationary parts. The channel is very large and has low fluid friction.
In the structure according to EP 1 168 622 A2, the very thin gap contains MRF, which has substantially worse coefficients of friction on account of the iron particles and high viscosity (similar to chocolate sauce). The structure according to EP 1 168 622 A2 resembles a sliding bearing and the structure resembles a rolling bearing here. A base torque of <0.1 Nm is not possible in the case of an MRF structure according to the shearing principle, which is intended to be able to be commercially used as a standard product.
In particular, the basic body comprises a base plate and an annular holding housing with a holding space arranged in the latter, the holding space being radially delimited to the outside by an outer limb of the holding housing extending substantially in the axial direction. The shaft is preferably rotatably held centrally on the holding housing. In particular, the electrical coil is held in the holding space. In particular, a circumferential ring which is connected to the shaft in a rotationally fixed manner adjoins the holding housing in a radially inner region and in a manner separated by a thin axial gap. The channel is preferably arranged in the holding space and is radially delimited to the outside at least substantially or completely by the outer limb and is radially delimited to the inside at least substantially or completely by the circumferential ring, with the result that a substantial part of the magnetic field from the magnetic field generation device runs through the holding housing, the channel and the circumferential ring.
At least one display unit is preferably assigned. The rotating unit preferably surrounds a display unit at least in sections.
At least one actuation sensor for sensing an axial actuation force and/or an axial actuation travel is preferably arranged on the basic body and/or the rotating unit.
The cited haptic operating devices have many advantages. A haptic operating device in which the rotating unit surrounds a display unit at least in sections or else completely is very advantageous since the user has a view of the display unit, in particular directly in the center of the rotating unit. As a result, the user can observe the changing display of the display unit during rotation of the rotating unit and need not allow his gaze to stray in order to track what effects the rotation of the rotating unit has on the technical equipment such as, in particular, a vehicle and particularly preferably a motor vehicle. The user can also rotate the rotating unit without looking at the operating device and can possibly operate and actuate the rotating unit without visual contact. However, the user always has the possibility of ascertaining, by means of a brief glance, the position in which the rotating unit is currently situated and what is currently displayed on the display unit of the haptic operating device. A considerable further advantage is that the user can use his operating hand to partially cover a display field behind it, whereas that display area of the display unit which is enclosed by the rotating unit is usually nevertheless freely accessible to the user's gaze.
When used in a motor vehicle, for example, the haptic operating device according to the invention makes it possible for the start menu (OFF-infotainment-ignition-start) to be hidden after the starting process since it is no longer required as long as the automobile is moving. It is not even permissible to switch off or start the vehicle when the gear is engaged.
In the case of self-driving vehicles for example, there is a desire for the gear shifter to disappear or for the gear shift etc. to be hidden during “self-driving”. In this case too, operation using the haptic operating device can now be dynamically (adaptively) adapted to the situation. Instead of the gear shift, it is possible to display the entertainment or, for example, parameters relevant to self-driving, for example distance, response behavior of the sensors etc.
In the case of self-driving vehicles or during autonomous driving, it may be problematic or dangerous if, for example, the vehicle containing the driver as the passenger automatically parks and the transmission selection lever for the gear shift remains here in the position selected last (for example “D”) for mechanical reasons even though the vehicle is in the reverse gear. It is no longer possible for the driver to intervene here since the displayed function does not match the executed function, which can confuse the driver. This also applies to the process of switching on the light (rotary switch) which is autonomous or is required during or for self-driving, the windshield wipers, the gas pedal, the brake pedal or other systems. Therefore, the practice of making all switching elements active using servo motors is much too expensive. The invention provides a remedy since the gear shift can be automatically changed to the parked position “P” when a vehicle is switched off. In contrast, the rotating unit can remain in the position in which it is situated when the vehicle is switched off. The next time the vehicle is started, the current position is interpreted as “P”.
In the case of automobiles, owing to the concentration on the road, it is also necessary for particular operating elements to be able to be actuated virtually “without looking” (that is to say “blind”). Haptic feedback additionally helps in this case.
The display unit is particularly preferably designed to display a symbol which is characteristic of a position of the rotating unit and is, in particular, a graphical symbol. It is possible for the display unit to display an operating state of the rotating unit and/or of the apparatus to be operated, such as a vehicle or a motor vehicle. It is possible and preferred for the operating state to be represented using a graphical symbol.
In all cases and configurations, the rotating unit can also be referred to as an operating unit.
A considerable advantage of a haptic operating device in which an actuation sensor for sensing an axial actuation is arranged is the fact that the haptic operating device cannot only be actuated by rotating the rotating unit but can also react to axial actuation forces. In such configurations having an actuation sensor, the actuation sensor is provided on and is particularly preferably fastened to the basic body and/or the rotating unit, in particular. The actuation sensor may sense an axial movement of the rotating unit relative to the basic body.
In particularly preferred configurations, a haptic operating device has a display unit on the rotating unit and at least one actuation sensor for sensing an axial actuation force.
The display unit is preferably connected to the basic body in a rotationally fixed manner, and the rotating unit is rotatable relative to the display unit. Such a configuration has the advantage that a display on the display unit does not change its angle during rotation of the rotating unit. As a result, the display on the display unit remains readable for the user in unchanged form. However, it is likewise possible for the display unit to be connected to the rotating unit in a rotationally fixed manner and to be rotatable, together with the rotating unit, with respect to the basic body. In the case of such a configuration, the viewing angle for the user does not change or changes only slightly if it at least partially rotates together with the rotating unit.
In preferred developments, at least one sensor which is used as an angle sensor is provided, which sensor can be used to sense an angle change between the rotating unit and the basic body. In this case, the sensor or angle sensor can detect relative angle changes. However, it is also possible for the sensor or angle sensor to sense an absolute angle between the rotating unit and the basic body. It is also possible for the sensor or angle sensor to sense an angle of between 0 and 360° in absolute terms, for example, but to be reset again after one complete revolution, with the result that angles of between 0 and 360° are always sensed during continuous rotation.
The sensor or the sensor used as an angle sensor preferably comprises at least two sensor parts, one sensor part being connected to the rotating unit and the other sensor part being connected to the basic body, in particular. For example, one sensor part may be in the form of a pulse generator, a measuring tape, a scale or the like and the other sensor part or the second sensor part may be used as a sensor or detector and may sense a relative movement of the first sensor part.
In preferred developments, the sensor or angle sensor is designed to sense an absolute angle position between the rotating unit and the basic body.
It is preferably possible to detect the direction of rotation. A high angular resolution is preferably possible. The finer the angular resolution, the earlier it is possible to recognize (or speculate) the wishes of the operator (reversal of the direction of rotation, finer adjustment). The control device (electronics/software) can react accordingly. A Hall sensor (EP 1 168 622 A2) is generally much too inaccurate for this purpose since only a few hundred “counts/revolution” are possible. The sensor or angle sensor is preferably designed to enable an angular resolution of 0.2° and, in particular, at least 0.1° or 0.05° or better. Angular resolutions of more than 100,000 “counts/revolution” (better than approximately 1/300 degree) are desirable. With an angular resolution of better than 0.2° or 0.1°, a movement pattern can be derived from extremely small movements.
In the case of low sensor resolutions, the “operating element” or the rotating unit or the rotary knob can remain with a “sticking” feeling (a high torque is needed for actuation), which haptically feels very unpleasant and is therefore very disadvantageous. In the case of a reversal of the direction of rotation at an end stop, for example, a high torque must then be initially applied even though the user wishes to carry out rotation in the opposite direction and a release can therefore be effected. Only the control device must initially “notice” that rotation is being carried out in the opposite direction. In this case, a high angular resolution helps considerably.
The (visible) part of the rotary knob (visible part of the rotating unit) particularly preferably does not form part of the magnetic circuit. The visible part of the rotary knob can particularly preferably have any desired design; the rotary knob can be chromium-plated or can be made of plastic or glass or can be covered with leather etc. since the rotary knob is a “design element”. This also relates to the assembly suitability (no screws visible; covering of the assembly hole etc.).
The transmission elements or rotating bodies (running rollers) are preferably rounded or cambered on the end face so that they axially have only point contact with the base plate or the cover. This considerably reduces the base friction and therefore the base torque.
It is possible to dispense with a contact ring.
The shaft is preferably magnetically conductive, thus reducing the size, weight and costs. The shaft preferably consists of a low-alloy steel, for example S235. So that the seal running thereon does not produce much friction and does not damage the shaft (race), the shaft is preferably hard-chromium-plated.
The circumferential ring preferably consists of steel having good magnetic conductivity or soft magnetic steel and is connected to the shaft in a rotationally fixed manner, in particular pressed.
The operating knob or the rotating unit is preferably connected to the shaft via a torque transmission element, for example a square with a slot. The operating knob or the rotating unit is braced without play by the torque transmission element (for example screwing using a countersunk screw).
In preferred developments and configurations, at least one control device is provided, the control device being suitable and designed to dynamically control the magnetic field generation device. The magnetic field from the magnetic field generation device is preferably dynamically generated on the basis of a rotational angle in order to provide a dynamic or adaptive and angle-dependent haptic latching pattern. In this case, it is particularly preferred for the haptic operating device to comprise the control device. The rotational angle can be derived from a relative or absolute angle position. It is also possible for an angle change to be used as the rotational angle. Such configurations are very advantageous since latching points at which the rotating unit practically engages can be dynamically provided over one or more angular ranges. It is also possible to dynamically generate end stops at which the torque needed for further rotation is considerably increased above a particular rotational angle in one direction of rotation or the other.
A control device is preferably provided and the control device is designed to accordingly rotate a representation of contents of the display device in the opposite direction on the basis of a signal from the sensor or angle sensor. Such a configuration is advantageous, in particular, in the case of a co-rotating display unit since the orientation of the represented contents is left substantially unchanged. For this purpose, the representation of the contents of the display unit can be rotated precisely by the same amount in the opposite direction by which the rotating unit is rotated. It is also possible for the rotation in the opposite direction to be carried out only to a certain extent. In these configurations, the represented contents on the display unit can remain substantially unchanged or even completely unchanged during rotation of the rotating unit.
The contents of the display unit can also be changed in a manner corresponding to the operator's viewing position. If the rotating unit or the operating element is operated, for example, by the driver in a motor vehicle, the display contents or the angle of the display contents is/are oriented toward the driver (for example in the 8 o'clock position). If the operating element is actuated by the front-seat passenger, the display contents are accordingly oriented, that is to say in the 4 o'clock position, for example. The haptic latching pattern or the latching positions is/are also adapted in association with this.
In this case, the haptic latching pattern can also vary the haptic torque. This is advantageous because the driver will operate the operating element with his right hand and the front-seat passenger will operate the operating element with his left hand. For most people, the feeling in the hands differs and this can be counteracted. Therefore, the latching pattern or the latching torque or the latching torque profile can be individually adapted to the operator via the rotational angle.
The menu may be entirely different if, for example, children rotate it (they are identified using keys, a fingerprint in the cover, smartphone, smartwatch). In this case, only restricted operation may then be possible (for example no hot temperatures, machines: no high speeds etc.) or operation of more sensitive, other latching patterns may be possible.
In the case of machines in companies, for example processing machines, or in the case of copiers, the menu and the latching pattern can change according to the operator. A warning can also be given via the haptic knob, which can prevent operating errors, particularly with new operating personnel, for example.
At least one separate contact element is preferably arranged between the two components. Such a contact element is preferably in the form of a contact ring and is used, in particular, as a friction ring and may be in the form of an O-ring, for example. The friction ring is used as a rotating ring and is preferably at least in occasional contact with at least one component. The contact element may have, in particular, a round cross section or else preferably a flat, flattened or else rectangular cross section.
Such a contact element or such a contact ring or friction ring makes it possible to ensure reliable contact between the two components or rolling contact on one of the components. The contact ring is particularly preferably elastic and can be produced or formed, for example, from a rubber material or from a rubber-like material.
A channel is particularly preferably formed between the two components, and at least a plurality of rotating bodies are particularly preferably provided in the channel.
The contact element or the contact ring or at least one contact ring or friction ring or friction element is particularly preferably arranged in an intermediate space or internal space between the two components. In particular, the contact element is arranged or fastened in the channel between the two components. For example, the contact element or the contact ring may be arranged in a circumferential groove on one of the two components. It is also possible for a contact element or a contact ring to be respectively provided on both components. At least one rotating body is particularly preferably in contact with at least one contact element/contact ring.
It is also possible for at least one rotating body to be equipped with at least one contact element or contact ring. For example, all or substantially all rotating bodies may each be provided with a contact element or contact ring. The contact ring may have any desired shape, for example a quad ring or a rectangular ring, without being restricted thereto.
The contact elements/contact rings between the components and/or the rotating bodies and the components ensure reliable contact between the contact element/contact ring and the two components, thus ensuring that, in the case of a relative rotation of the two components with respect to one another, the rotating body co-rotates at least for most of the time.
Such a configuration is particularly advantageous if the intention is to use the wedge effect for wedging magnetorheological particles.
A configuration without the use of (flexible) contact elements or contact rings enables even lower base friction and is therefore particularly preferred.
The basic body preferably comprises a base plate and a holding housing, and a shaft is rotatably held on the holding housing. The magnetorheological medium is preferably held between the basic body and the shaft. For example, the magnetorheological medium may be held in an internal space of the holding housing.
rotating unit is preferably connected to the shaft in a rotationally fixed manner. The connection can be effected using a force fit and/or a form fit.
In advantageous configurations, the shaft is rotatably supported at one end on the base plate. In particular, the shaft is resiliently supported on the base plate using one end. This makes it possible to preload the shaft in a defined position.
The basic body and the shaft preferably each have a circumferential running surface for the rotating bodies adjacent to the base plate. The running surface(s) may be provided on a cylindrical, convex or concave or else conical circumferential surface.
At least one running surface preferably has at least one circumferential groove for the rotating bodies and/or for at least one contact element or at least one contact ring. This ensures that the contact ring and the rotating bodies assume a defined position.
In advantageous configurations, the running surface of the shaft is formed on a circumferential ring with an increased diameter. In preferred developments, a holding space, in particular an annular holding space, in which an electrical coil is arranged as the magnetic field generation device, is formed in the holding housing. In all configurations, the electrical coil may also be arranged at other locations or at or in other forms of recesses.
The electrical coil is preferably arranged substantially axially adjacent to the rotating bodies. This makes it possible to ensure that the magnetic field generated by the electrical coil acts, to a high degree, on the rotating bodies or the channel and the magnetorheological medium contained in the latter.
The circumferential ring is preferably separated, on an end face, from an end face of the holding housing by a gap. A free axial distance in the gap is preferably considerably shorter than a free radial distance at the channel. The free radial distance at the channel results from the radial distance between the two components and, in particular, from the free radial distance between the circumferential ring and the end face or running surface in the holding housing. In particular, the end face is an axial surface but may also be part of a lateral surface of a cone. A ratio of the free axial distance to the free radial distance is preferably less than 1 to 2 and, in particular, less than 1 to 5 and preferably less than 1 to 10.
In preferred configurations, the holding housing and the circumferential ring consist substantially or completely of a material with better magnetic conductivity than the base plate. This makes it possible to ensure an effective flux of the magnetic field.
The actuation sensor preferably senses a distance or a measure of a distance between the basic body and the rotating unit.
In all configurations, it is preferred for a free distance between the rotating body and the component or at least one component to be at least twice as large as a typical average diameter of the magnetically polarizable particles in the magnetorheological medium. At least one region containing the magnetorheological medium is preferably provided between the rotating body and at least one component, the magnetic field from the magnetic field generation device being able to be applied to said region in order to selectively concatenate the particles and/or wedge them with the rotating body and/or release them.
The region which contains the magnetorheological medium and at which the particles selectively concatenate and/or wedge with the rotating body has an acute angle, in particular, in the activated state.
It is also possible for the magnetorheological particles to be concatenated in the channel without using rotating bodies.
If rotating bodies are used, the region, in particular the acute-angled region, between the rotating body and a component preferably tapers in the direction of the relative movement of the component relative to the rotating body.
In particular, the two components can be coupled to one another selectively and in a controlled manner.
In the sense of this application, the term “coupling intensity” is understood as meaning the coupling force and/or the coupling torque between the two components. If linear force transmission is desired, for example, the coupling intensity corresponds to the coupling force. If a torque is intended to be transmitted, the coupling intensity is used to mean the coupling torque.
The viscosity of the magnetorheological medium can preferably be changed by the field, as a result of which it is possible to influence the displacement work needed for the relative movement of the components and/or rotating bodies which can be moved relative to one another.
Displacement work is also understood as meaning the displacement force needed to displace the medium during a relative movement.
A considerable and surprising advantage of the magnetorheological transmission apparatus used results from the considerably intensified effect of the magnetic field from the magnetic field generation device in the channel. The acute-angled region containing the medium acts as a lever and therefore virtually like a strong mechanical lever transmission, the lever considerably intensifying the effect of the magnetic field by a multiple. As a result, either the field strength of the magnetic field generation device can be reduced with an effect which remains the same or else the effect of the magnetic field is intensified with a field strength which remains the same or the effect is even considerably increased with a reduced field strength. The acute-angled region containing the medium increases the effect by a multiple, in particular, if the magnetic field acts on the medium. In particular, the magnetic field acts at least occasionally on the acute-angled region which contains the magnetorheological medium or is formed.
As a result of the fact that the rotating body is arranged at a considerable free distance from the at least one component, a macroscopic wedge which can be used to transmit strong clutch or braking torques can be produced. Considerable construction volume can be saved as a result of the completely surprising multiplication of the effect. The effect used is based on the wedge formation (cluster formation) and not only the magnetorheological concatenation of individual particles. The typical reaction time for the wedge formation requires several milliseconds, while individual particles are concatenated according to the MRF effect already within approximately 1 millisecond. This time duration, which is multiple times longer, is due to the wedge formation. Such a considerable intensification of the effect was not expected. The longer reaction time of, for example, 5, 10, or 20 milliseconds is more than sufficient in many applications.
The channel can also be an intermediate space or a space which is open on four sides.
An acute-angled region of the channel is defined as that channel region which appears approximately to have an acute angle in at least one cross section through the shape of the rotating body and components. The sides of the region do not have to be straight and can also be curved and/or have another contour. The acute-angled region defines that part of the channel in which the rotating body and components are at the shortest distance from one another, in particular, or touch, and the adjoining region, in which the surfaces of the rotating body and components move away from one another.
Under the effect of a magnetic field, the acute-angled region containing the magnetorheological medium is formed, in which a considerably increased viscosity is present.
A good torque to weight ratio, which can be greater than 100 Nm/kg, is possible.
A rotating body is preferably set into a rotational movement by a relative velocity in relation to at least one component. It is possible for the circumferential velocity of the rotating body to be equal to the relative velocity in relation to the component. However, it is also possible for the circumferential velocity of the rotating body on its outer surface to be greater than or less than the relative velocity. In particular, it is possible for the circumferential velocity of the rotating body on its outer surface to be less than the relative velocity of the rotating body in relation to the component.
The rotating body can be designed to be substantially rotationally symmetrical around at least one axis of rotation. It is likewise possible for the rotating body to be designed to be rotationally symmetrical around a plurality of axes of rotation. For example, the rotating body can be in the form of a sphere or ellipsoid. It is also possible for the rotating body to be in the form of a cylinder, roller, or generally a rolling body. In particular, an approximately cylindrical configuration has proven to be advantageous since, in the case of a cylindrical rotating body, for example, the acute-angled region containing the medium forms over the entire width of the rotating body and is thus substantially wedge-shaped. In these and other configurations, the acute-angled region has a wedge shape.
However, it is not necessary for the rotating body to be rotationally symmetrical. Rotating bodies having elliptical or egg-shaped cross sections or rotating bodies having indentations like golf balls or having regular or irregular indentations and/or protrusions can also advantageously be used. The surface of the rotating bodies can be smooth, but does not have to be. Since the rotating bodies are not used to mount and support the components relative to one another, a symmetrical and/or smooth surface is not necessary. Rotating bodies having a rough and/or irregular surface can even be advantageous since the wedge effect is intensified. Increased wear does not occur since the rotating bodies are not used for mounting and transmitting load-bearing forces.
The effect is preferably not intensified solely due to intensification or bundling of the magnetic field, but rather above all also due to the particles clustered in front of the rotating bodies or rollers and the compaction thereof. Owing to the magnetic field, the particles cannot move away and thus compact more rapidly to form a wedge. The wedge can be externally controlled easily via switch. The advantage in the case of magnetorheological fluids such as MRF is that the wedge can disengage again by canceling the magnetic field. The wedge can be influenced using the magnetic field—without mechanical movement or force introduction. It has proven to be advantageous for targeted influencing and reliable control that the free distance between the rotating body and the component is greater than a multiple of the particle diameter.
The diameter of the particles of the magnetorheological medium is between 1 μm and 10 μm, in particular. The typical mean diameter of the particles of the magnetorheological medium is the arithmetically averaged diameter of the particles which are larger than the smallest percent and which are smaller than the largest percent. As a rule, this value corresponds to the mean value of the diameters of the largest and the smallest particle, that is to say 5.5 μm in the selected example. If, however, for example, a very small number of even smaller particles are present, this does not change the typical mean diameter thus determined. The same applies if, for example, individual particles having a diameter of 10.5 μm or 11 μm are to be included.
The free distance between the rotating body and the component is preferably greater than 30 μm and, in particular, less than 300 μm. The typical mean diameter of the particles is preferably between 3 μm and 7 μm. The free distance between the rotating body and the component is preferably greater than 70 μm and, in particular, less than 250 μm.
The acute-angled region advantageously wedges the two components, which are freely movable relative to one another without a magnetic field, upon application of a magnetic field. A mechanical wedge in the form of a separate fixed part is not required for this purpose.
The acute-angled region is preferably provided between the body and one component in such a manner that the acute-angled region tapers in the direction of the relative movement of the component relative to the rotating body. If a cylindrical rotating body rolls on a flat surface of one component, the acute-angled region forms in a wedge shape in front of the rotating body. A wedge which is concatenated as a whole and inhibits the relative movement of the rotating body to the component arises due to the concatenation of the particles in the medium.
The rotating body and, in particular, each rotating body is particularly preferably in the form of a separate part between the first and second components. It is then preferred for one component, as the outer component, to surround the other component, as the inner component. For example, a (drive) shaft can be provided as the inner component. The other or outer component can be used for braking, for example, and can radially surround the shaft. The rotating bodies can be provided between the shaft and the outer component. It has been shown that rotating bodies which rotate around their own axis are considerably better for achieving the wedge effect. Finished bearing shells are not necessary. The transmission of a clutch or braking torque functions independently of the quality of the rolling surfaces.
At least one separate bearing or roller bearing is provided for mounting the two components. The rotating bodies ensure, with the wedge effect, the transmission of the desired torques, while the roller bearing or bearings ensure(s) the defined guiding and support of the two components and the uniform running gap.
A transmission may also be arranged or kinematic levers can be used between the drive shaft and the rotating body or between the rotating body and the basic body/housing. As a result, the torque and the rotational angle can be varied in a wider range or the haptic operating knob can have a smaller construction and the construction volume can therefore be considerably reduced. The transmission may be in accordance with the prior art, preferably a planetary transmission or harmonic drive which is free of play as far as possible.
In all configurations, the free distance is preferably at least twice, five times and, in particular, ten times as great as the largest typical particle diameter. In specific configurations, a free distance of between approximately five times and, in particular, ten times and twenty times the largest typical particle diameter has proven to be advantageous. In the case of larger free distances, the maximum transmittable torque is reduced again since the wedge effect subsides. In the event of excessively short free distances, a blockade can occur even without a magnetic field. In addition, disengagement of the wedge after the shutdown of the magnetic field then cannot always be ensured.
The mean particle diameter is understood as meaning the arithmetic mean of minimum and maximum particle diameters. Most MRF have magnetically polarizable particles which have a size distribution of between approximately 1 μm and 10 μm. The mean particle diameter is 5.5 μm in this example. In the case of variable size distributions, the largest typical particle diameter is understood as meaning a particle diameter which is exceeded by only fewer than 1% of the particles. The largest typical particle diameter is somewhat less than 10 μm in the mentioned example, so that 10 μm can be presumed to be the largest typical particle diameter here.
The free distance is preferably greater than 1/500 and preferably greater than 1/250 and, in particular, greater than 1/100 and particularly preferably greater than 1/50 of a diameter of at least one rotating body, and, in particular, the free distance is less than 1/10 and, in particular, less than 1/20 of the diameter of the rotating body.
The free distance is preferably greater than 1/300 of the external diameter of the inner component and/or greater than 1/500 of the internal diameter of the outer component. The free distance is preferably greater than 30 μm and in particular less than 200 μm.
Variations by +/−20% are preferably possible in the case of all numeric specifications. A particle is understood below as meaning a magnetically polarizable particle.
If oversized rotating bodies and/or shaft diameters are used, other distances can be advantageous. An advantage of this magnetorheological transmission apparatus having at least two components which can be coupled is that the wedge formation is manufacturing tolerant, that is to say, for example, manufacturing-related and installation-related differences in gap heights, surfaces, dimensions and also thermal expansions or load-related shifts of components have a minor influence thereon and cause negligible torque or force differences.
For example, a structurally related change of the gap within certain system limits can also be detected by sensors and worked out by field adaptation, for example.
In preferred configurations, the rotating body is part of the first or the second component. This means that the rotating body, which is in the form of a rotating body, for example, is part of the first component and rolls on the second component, for example. The rotating body can also be without mechanical connection to both components, however.
In the acute-angled region, which is wedge-shaped, for example, the ferromagnetic particles concatenate in the medium upon application of an external magnetic field and result in a locally more solid structure which opposes the further relative movement between the rotating body and the adjacent component. The particles in the wedge-shaped part can be additionally compacted in the direction of movement in front of the rotating body by the rolling movement of the rotating body. However, depending on the design of the rotating body, this compaction can also be performed by pitching, tilting, or other movements relative to a component.
For example, if the rotating body rolls on the surface of one component and such an acute-angled region forms in front of the rotating body, particles in the medium are entrained and set into rotational movement by the outer surface due to the rotational movement of the rotating body, but the hardening acute-angled region strongly opposes such a rotational movement. The acute-angled region in wedge shape results in a force on the rotating body away from the component. Such a force and a movement resulting therefrom can optionally also be used for fine adjustment purposes. A rotational movement can preferably be converted into an axial displacement of the rotating body by the acute-angled region in wedge shape when the magnetic field is activated. The rotating body is thus virtually caused to float by the particles. It is also possible to provide the rotating body or a component with thread-shaped notches, for example, or to mount them at an incline relative to one another, in order to change the effective direction of the resulting force or to further increase the achievable force transmission. A linear movement can thus be converted into a rotational movement using a type of threaded rod. The relative movement is inhibited by applying a field.
It is likewise preferred for the rotating body to be in the form of a separate part between the first component and the second component. Such a configuration can be particularly advantageous since two acute-angled regions or wedge-shaped regions can occur between the rotating body and the two components. If the rotating body practically rests against the first component on one side and practically rests against the second component on the other side, acute-angled regions which are subjected to the magnetic field from the magnetic field generation device form on both sides. The effect is thus increased. It is not necessary for this purpose for the rotating body to rest completely against the first component or the second component. A small gap remains between the rotating body and the respective component. The size of the gap is dependent, inter alia, on the properties of the medium. In particular, the size of the gap can be at least five times and preferably at least ten times or twenty times a typical or mean particle diameter.
The ferromagnetic particles consist, in particular, of carbonyl iron powder. The fluid can be an oil, for example.
It is also possible for magnetorheological and electrorheological media to be used jointly. The use of other media which are influenced and concatenated, for example, by corresponding fields is also conceivable. It is likewise possible to use media which change their rheological properties depending on other physical variables such as temperature or shear velocity.
The channel can be completely or also only partially filled with the medium. At least the acute-angled region of the channel is preferably filled with the medium.
In all configurations, the first and/or second component can be rotationally symmetric. For example, the components can each be in the form of plates or cylindrical bodies, between which rotating bodies are provided, in order to increase the effect of the magnetic field from the magnetic field generation device accordingly through the wedge effect.
In all configurations, it is preferred for the magnetic field to run through the rotating body and, in particular, substantially transversely to the relative movement of the components relative to one another and from one component to the other component at least partially through the rotating body. Such a configuration has proven to be particularly effective since the effect of the magnetic field at the transition points from the rotating body to the walls of the channel is particularly strong. Depending on the acting magnetic field, it is therefore advantageous if the rotating body is at least partially magnetically conductive. In particular, at least one component and in particular both components and/or the at least one rotating body is/are made at least partially of a ferromagnetic material. The relative permeability is preferably greater than 500. The relative permeability of the material can also be 1000, 2000, or more. Rotating bodies made of a ferromagnetic steel, such as ST37, are possible, for example.
The material can be demagnetized by a damped magnetic alternating field, so that a lower base torque is achieved without a residual field.
In all configurations, it is preferred for the magnetic field generation device to comprise at least one permanent magnet and/or at least one coil. It is also possible to use one or more permanent magnets and one or more electrical coils.
It is possible and preferred to permanently change the magnetization of the permanent magnet by means of at least one magnetic pulse from an electrical coil. In such a configuration, the permanent magnet is influenced by magnetic pulses from the coil such that the field strength of the permanent magnet is permanently changed. The permanent magnetization of the permanent magnet can be set by means of the magnetic pulse from the magnetic field generation device to an arbitrary value between zero and the remanence of the permanent magnet. The polarity of the magnetization is also variable. A magnetic pulse for setting a magnetization of the permanent magnet is, in particular, shorter than 1 minute and preferably shorter than 1 second and the length of the pulse is particularly preferably less than 10 milliseconds.
As an effect of a pulse, the shape and strength of the magnetic field are permanently maintained in the permanent magnet. The strength and shape of the magnetic field can be changed by means of at least one magnetic pulse from the magnetic field generation device. The permanent magnet can be demagnetized by a damped magnetic alternating field.
AINiCo, for example, is suitable as a material for such a permanent magnet with variable magnetization, but other materials having comparable magnetic properties may also be used. In addition, it is possible to produce the entire magnetic circuit or parts thereof from a steel alloy with strong residual magnetism (high remanence) instead of a permanent magnet.
It is possible to use the permanent magnet to generate a permanent static magnetic field which can have a dynamic magnetic field from the coil superimposed on it in order to set the desired field strength. The current value of the field strength can be varied arbitrarily by the magnetic field from the coil. It is also possible to use two separately controllable coils.
In all configurations, it is preferred to provide at least one control device. It is also possible to use an energy store, for example a capacitor, to store at least a fraction of the required energy. At least one sensor or a plurality of sensors can be used to detect relevant data, for example the relative velocity of the components in relation to one another or the prevailing field strength and the like. It is also possible to use a temperature sensor as the sensor, which triggers an alarm if predetermined temperature conditions are exceeded, for example. A rotational angle encoder can advantageously be used to have data relating to the angle position of the components in relation to one another at any time.
In all configurations, it is preferred that the permanent magnet at least partially consists of a hard magnetic material whose coercive field strength is greater than 1 kA/m and, in particular, greater than 5 kA/m and preferably greater than 10 kA/m.
The permanent magnet can at least partially consist of a material which has a coercive field strength of less than 1000 kA/m and preferably less than 500 kA/m and particularly preferably less than 100 kA/m.
The magnetorheological transmission apparatus is part of an operating device which comprises, in particular, an operating or control knob or the like.
The rotating body and at least one component can touch at at least one point or on at least one line. It is possible and preferred for the rotating body to be at rest relative to at least one component.
The rotating body can preferably move relative to at least one component, for example in the form of a rotational or tilting movement.
The field strength can have a strong gradient depending on the respective distance between the rotating body and components.
The field strength preferably increases in the acute-angled region between the rotating body and components toward the region having the shortest distance.
The need for maintenance is low since few and simple parts are used. If necessary, the maintenance can be carried out by simply replacing the magnetorheological fluid. The structure is simple and robust and power feedthroughs are not required. In addition, the energy requirement is lower than in the prior art because the wedge effect substantially contributes to influencing the relative movement of the components. It is possible to achieve a torque/weight ratio of >100 Nm/kg.
In magnetorheological clutches or brakes without a wedge effect, the magnetic field poles move relative to one another and generate shear forces (direct shear mode) in the interposed MR fluid. The shear forces vary depending on the magnetic field. No magnetic field means no or low shear forces (no chain formation in the MRF), maximum magnetic field means maximum shear forces and therefore maximum braking force or braking torque. In simplified form, the magnetic field and shear forces are proportional.
In the present invention, through appropriate design of the individual components, dimensioning, and field introduction, a very advantageous behavior which deviates therefrom can be provided. This advantageous behavior is expressed in that a substantially lower magnetic field, and therefore a lower current intensity, is needed to maintain the acute-angled embodiment or the MR fluid wedge than is needed for the initial generation of the wedge. This is because the particle cluster no longer falls apart so easily once it has first been accumulated and has been quasi-mechanically compacted by the special movements fundamental to this invention under the influence of a correctly introduced magnetic field. As a result, for example, after a corresponding time for achieving this state, a braking torque can be maintained using the fraction of the magnetic field or electrical power (coil current), which is advantageous in terms of energy.
If clutches having magnetorheological fluids according to the prior art are loaded beyond the maximum transmittable clutch torque, individual particle chains begin to break apart, whereby slip or slipping through results. The maximum clutch torque is maintained, however, or sometimes even slightly increases, and the clutch does not disengage. Depending on the application, this can be undesirable, for example if a drill bit of a drill jams during drilling.
In the present invention, through appropriate design of the individual components, dimensioning, and field introduction, a very advantageous behavior which deviates therefrom can be provided. This advantageous behavior is expressed in that, if a maximum force is exceeded between the moving parts, the wedge (material cluster) generated by the magnetic field is suddenly pressed through the gap (material displaced) and the force decreases suddenly at the same time. On account of the relative movement resulting therefrom and the high applied force, a new wedge does not form, as a result of which the relative force remains low. In the case of overload clutches, this behavior is very advantageous. The maximum force (triggering force) or the maximum torque (triggering torque) can be preset via the magnetic field.
Furthermore, demixing, sedimentation, and centrifugal force problems are reliably avoided since continuous mixing of the particles in the medium is achieved by the rotating bodies which are rotating.
On account of the substantially higher transmittable torques and forces, it is possible to implement clutches, brakes or the like having substantially smaller diameters. On account of the low MRF channel height and the rotational movement of the rotating bodies, demixing is practically not relevant in the case of the present invention.
The invention can be used in manifold ways. Use as an operating element on domestic appliances such as washing machines and also to choose the operating state of vehicles is possible.
The invention can also be used in the case of a three-dimensional movement. The rotation and pendulum movement can thus be restricted or blocked by the MRF wedge. The acting torque is continuously adjustable and switching times in the range of a few milliseconds can be achieved. The structure is simple and no mechanically moving parts are required for varying the torque. A further advantage is that almost noiseless operation is possible. The additional costs are low and a magnetorheological transmission apparatus according to the invention can be designed to be operationally reliable if, for example, a permanent magnet with remanence is used to set a magnetic field. The wedge effect enormously intensifies the effect, with the result that a smaller installation space is achievable.
In all configurations, the rotating bodies do not have to be smooth, but rather can have rough or uneven surfaces.
The haptic operating device can be used in manifold ways and comprises, for example, controllers for crane operation or the like. In this case, the rotation can be controlled more stiffly, depending on the load. It can also be controlled on the basis of the load height.
The use in “force feedback” applications or in “steer by wire” applications, such as in the steering wheel, gas pedal or brake pedal, is also of interest. The use on operating elements in vehicles, steering wheels, automobile radios, windshield wiper switches, home appliances, stereo systems, remote controls, cameras, test stands, oscilloscopes, operating apparatuses, robot controllers, drone controllers and when positioning military weapons etc., is also possible.
In all configurations, it is also possible to use magnetic seals to seal an apparatus according to the invention, in addition to a seal with a sealing lip. The seal can be produced via a permanent magnet here. Advantages of such a configuration are smaller base forces, freedom from wear, and the permissibility of greater manufacturing tolerances. In addition, there is a defined overload behavior since a defined breakthrough occurs if the overload is exceeded. It is possible to use such a seal in front of or behind an apparatus according to the invention or to use it in front and behind.
A significant advantage of the magnetic seal is the very low friction; however, it can be necessary to use yet another seal since such a seal possibly only holds back MRF particles and allows oil as the base fluid to pass through the gap over time, for example. Therefore, such a magnetic seal can be used as an outer seal in order to hold back MRF particles. A further seal, for example a conventional seal, then only seals off the carrier medium.
A movement of the magnet can be used to achieve lubrication in the MRF, as well as material transport and cooling, for example via hydrodynamic effects. In addition, a flow away from the seal can be achieved and pressure differences can be dissipated.
In order to set the play between two parts, for example, or to remove play from a design and to compensate for manufacturing tolerances, for example, it is possible to use a force or an axial force and/or a radial force which is caused by an MRF wedge effect.
In all configurations, it is preferred to provide a settable permanent magnetic field strength via remanence. In preferred embodiments, a bearing having a magnetorheological transmission apparatus according to the invention has no or only minimal residual magnetism (remanence) itself. Otherwise, a position-dependent counterforce of different strength can occur since the parts move in relation to one another.
In advantageous configurations, the remanence material should be arranged in a general region of the bearing which is permeated, in particular, by the magnetic field in a position-independent manner, thus, for example, the inner shaft or the outer shell etc.
However, it is also preferred to use the effect of the position-dependent magnetization by using, for example, the inner running surface having remanence in order to generate specific latching torques, for example. This can be performed, for example, for haptic feedback about variable latching torques with respect to their strength, the rotational angle, or the end stop or the like. Not all bearing balls have to be ferromagnetic, depending on the desired setting capability.
It is also possible to provide a magnetorheological transmission apparatus having a design deviating from the conventional bearing structure. For example, the direction of the magnetic field can also be oriented at least partially or completely approximately parallel to the axis. At least partial orientation parallel to the rotational direction or movement direction or in the tangential direction is also possible. It is also possible for the entire magnetic circuit to be arranged nearly or completely in the interior or on the end face.
The material of the magnetorheological transmission apparatus does not have to be completely ferromagnetic; depending on the desired application or magnetization, it can be advantageous if individual parts of the magnetorheological transmission apparatus are not ferromagnetic or are only partially ferromagnetic.
Depending on the application, it is also conceivable to manufacture at least one part from different materials, to obtain locally differing magnetic properties.
The haptic operating device preferably functions with a magnetorheological transmission apparatus with a wedge effect. The position or the rotational angle of the rotary knob can be determined via the rotary encoder and the rotational resistance can be varied in a wide range. Thus, for example, a haptic interface with variable latching torques and arbitrarily settable end stop can be constructed, which changes its properties depending on the currently selected menu. A low or high torque and/or a small or large latching pattern/ripple and also a variable latching pattern—depending on the menu to be operated—can be set. The profile of the torque increase and decrease can be set or varied depending on the situation, for example as a square-wave, sinusoidal, sawtooth, or arbitrary profile. A stop can also be simulated. The stop can be hard or can have a predefined or situation-dependent torque profile. The torque profile can be different during rotation in one direction than during rotation in the other direction.
The rotary knob as one component is preferably fixedly connected to the shaft as the other component which is in turn rotatably mounted in the housing. The relative movement or relative position is detected via a rotary encoder, for example via a magnetic, optical or (via buttons) mechanical incremental encoder. A potentiometer with sliding contacts can also be used, but only specific rotational angles are usually permissible using said potentiometer.
A sealing ring is advantageous so that the magnetorheological fluid remains in the housing. The seal can also only consist of permanent magnets or a combination of a permanent magnet and a conventional seal.
The inner region, i.e. the volume enclosed by the seal and housing, is at least partially filled with a magnetorheological fluid.
The housing is preferably designed as a pot, i.e. it is closed on one side. Only one sealing ring is thus required. A continuous shaft (two-sided shaft) is also conceivable.
The coil can generate a magnetic field, wherein the magnetic circuit is closed via the housing, the shaft, and the magnetorheological transmission apparatus. The magnetic field required for the wedge effect can thus build up in the magnetorheological transmission apparatus. The coil is advantageously fixedly connected to the housing, which makes the cable routing easier.
The structure is robust and can be designed such that almost no magnetic stray fields are generated outside the housing. However, many other structure variants are conceivable, which can have specific advantages depending on the application.
For example, the coil can also be arranged outside the housing, the magnetic field then acting on the magnetorheological transmission apparatus through the housing. No mechanical connection is necessary here between the coil and the housing; the coupling of the magnetic circuits is sufficient to influence the magnetorheological transmission apparatus in the housing. In particular, the coil does not have to be permanently on or in proximity to the housing and can be designed such that it can be removed from the housing as a separate unit. Permanent magnets can also be provided in the magnetic circuit.
In a preferred embodiment, the rotary knob can be electromagnetically driven, for example, and can also actively exert a force (force feedback) in order to be able to statically generate a specific countertorque. In this design, a better torque to installation space ratio is achieved than in many designs according to the prior art. In addition, the production costs are low because of the simple structure since, for example, the rolling surfaces of the components do not have to be highly precise in haptic applications and also generally do not have to withstand high speeds and a large number of revolutions. In general, the magnetorheological transmission apparatus described here has a very low base friction (OFF state). A battery and a control command transmission unit (radio, WLAN, Bluetooth, NFC, antenna) are preferably also integrated in the actuator or rotary knob. The haptic knob can then be placed anywhere and does not require a wired control connection or current connection. The MRF wedge principle requires very little current (power) in relation to the torque. It is therefore also highly suitable for battery operation or for wireless energy supply. Both the required energy and control commands and also, for example, measured values from sensors such as rotational angles can be transmitted wirelessly.
A preferred embodiment manages without a battery and receives the energy required for the function by means of inductive coupling. Embodiments which acquire the energy required for operation directly from the environment and buffer it locally (energy harvesting) are also particularly preferred. Thermoelectric generators, solar cells, elements which convert vibrational energy into electrical energy, and others, as well as corresponding local energy stores are possible for the energy conversion. It is also conceivable to use the movement of the magnetorheological transmission apparatus itself to generate energy.
If a magnetic field is applied to the magnetorheological transmission apparatus at least partially via a permanent magnet, and the magnetization of the magnetic field is permanently changed by at least one magnetic pulse from at least one electrical coil, several advantages result. In specific cases, weight and space advantages can be achieved, for example by using the remanence and the pulsed operation of a coil which does not always have to be energized. The wires of the coil can be dimensioned to be thinner and lighter because they are each energized only for a short operating time. This can result in advantages in the case of weight, power demand, space requirement, and costs.
Therefore, it can be advantageous in specific applications that, due to the pulsed operation of the electrical coil, it can be significantly smaller than if it must be designed for a switched-on duration of 100%. The heating of the coil usually does not play a role in pulsed operation since short-term power loss peaks are buffered by the intrinsic heat capacity of the coil and the parts surrounding the coil. Very high current densities in the turns can thus be tolerated or thinner lines can be used, as long as the mean power loss remains acceptable over longer periods of time.
In the case of a smaller coil, the magnetic circuit surrounding the coil can also usually be smaller, which is why a comparatively large amount of installation space, material, weight, and costs can be saved. Only the energy expenditure for a single pulse increases here, but this can be very well tolerated depending on the application.
Overall, a large amount of energy can nonetheless be saved in comparison with a continuously energized coil.
In all configurations, it can be possible to supply the power in a wireless manner. The power can be supplied, for example, from the current source to the power electronics or from the power electronics to the coil via electrical, magnetic, or electromagnetic coupling, for example a radio link. When used in a bicycle, the power can be supplied externally via a docking station, for example. It is also possible to supply energy to all loads (forks, rear shock absorbers, display) via an energy source on a bicycle, for example. The power can also be supplied similarly in the case of a ski boot, ski, mobile telephone, or to the sensors.
An energy supply via radio can possibly have worse efficiency than conventional wiring. In addition, the energy transmission and its range can be limited. However, such disadvantages do not interfere depending on the application. It is advantageous that no wear of the contacts occurs. The energy transmission is usually secure from polarity reversal and short-circuit-proof since only a limited power is present on the secondary side. Furthermore, cable breaks are not possible and the apparatus is more movable as a whole.
In such configurations, however, it is advantageous to buffer the energy for at least one pulse in a capacitor or energy store. The energy supply of the system can thus have a smaller power since short-term power peaks of a pulse are absorbed by the capacitor. In addition, a discontinuous or pulsed energy supply can also be used.
One possible expansion stage of the present invention is a fully autonomous system which is wirelessly supplied with energy. For example, use on a bicycle is conceivable, in which case the system is supplied with energy by at least one small magnet on a tire.
In general, arbitrary “energy harvesting” units can thus be used to supply energy, for example solar cells, thermoelectric generators, or piezoelectric crystals. Elements which convert vibrations into energy can thus also be used very advantageously for the supply.
An embodiment similar to that in an electric toothbrush is also conceivable, in which the energy is supplied by inductive coupling. For example, the rechargeable battery can be inductively charged, without damaged cables or corroded or soiled contacts obstructing the charging process. Energy can be transmitted over longer distances via magnetic resonance.
The power supply of the remanence pulse can be effected via induction, as in the case of electric toothbrushes. The combination of the MRF wedge principle with remanence is particularly power-saving and advantageous.
A loudspeaker or a noise generating unit can also be integrated or assigned. This is advantageous since the rotary knob as the MRF wedge knob is mechanically noiseless per se. Both the rotation without and also with a latching pattern and/or the virtual stops are noiseless per se. The generation of the MRF wedge for a torque increase or to generate a latching pattern is likewise noiseless per se. By means of the noise source, such as a loudspeaker or a piezoelectric loudspeaker, for example, clicking can be associated with the virtual latching pattern at each latching position. The type, volume and duration of the noise can be individually assigned, but can also be changed or turned off if the user wishes.
Therefore, the torque, the latching pattern, the stops and the noise are programmable or adaptive. The noises can also be generated via external loudspeakers, for example standard loudspeakers in the automobile or the loudspeakers of the hi-fi system in the home.
The haptic knob can therefore practically replace the mouse wheel of a computer mouse. In the case of the latching pattern, not only the angular distance of the latching pattern can be settable, but rather also its profile shape, thickness etc. A latching pattern characteristic curve can therefore more or less be predefined.
The haptic rotary knob can also be mounted on an operating surface or on a screen. So that the display does not have to be removed for fastening the knob, it can consist of an upper part on the display and a lower part below the display. Data transmission via induction or the like, for example, is preferably provided. The display can thus be produced more cheaply as a surface.
It is also possible for an MRF haptic knob to also be pressed. The pressing can also act through an MRF whose properties are variable via a magnetic field.
The screen displays the information to be set which changes depending on the application. The function of the haptic knob is adapted thereto. In one case, adjustment is made by means of a latching pattern (for example setting the volume; a volume scale which can also have a logarithmic scale appears on the display).
In another case, adjustment can be made between two positions without a latching pattern, but with variable torque, thus, for example, between the 8:00 position and the 16:00 position or between the 4:00 position and the 8:00 position, in which case an increasing torque can be provided in each case before the end position. The latching pattern can also be used to approach defined positions, for example if a name input is requested.
The display can also be in the form of a touchscreen. Menu items can thus be rapidly selected and fine adjustments can be made by means of the rotating actuator. For example, it is not desirable in the case of automobiles to control the volume of the radio via touchscreen since the driver would otherwise always have to look for a long time at what and where he is currently adjusting, which distracts him. He also finds the rotating actuator with a brief glance or without looking at it.
The haptic operating element can also be globally displaceable on guides or kinematic levers. The haptic operating element which has a very compact and low construction can therefore be mounted above a display, for example. Depending on the position of the haptic operating device above the display (almost like the mouse pointer of a screen mouse), the underlying menu is haptically and dynamically adapted.
The adjustment using a mechanical actuator is also simpler and safer than via a touch display when cycling, for example. This is also true, in particular, if the cyclist is wearing gloves, for example, whereby the operation of a touch display is difficult or even impossible.
A combination of a display or touch display and a mechanical rotating actuator with variable torque/latching pattern is also possible. Such input devices can also be advantageous outside the motor vehicle, thus, for example, in the case of controllers for industrial installations, remote controls for televisions or radio vehicles such as toy helicopters, for example, and on PCs and games consoles, and control consoles for military applications (drone aircraft, rockets).
It is also possible for a haptic rotary knob with a display to replace the current computer mouse.
It is possible for the rotary knob or the actuator to be countersunk in the normal state and to be extended only if needed.
It is also possible to embody such a structural unit as a slide controller, in particular in combination with a linear MRF wedge unit.
It is also possible to equip a magnetorheological transmission apparatus with one or more poles and one or more elevations. In all configurations, it is possible for elevations or the like, which protrude from one component in the direction of the other component, for example, to be provided between the two components of the magnetorheological transmission apparatus.
Such a configuration is possible and preferred both in the case of rotational mobility and in the case of linear mobility of the two components with respect to one another.
Only one elevation can be provided or a plurality of elevations can be provided. It is possible for a ball or a roller or another rotating body to be arranged on at least one elevation and to be at least partially accommodated by the elevation.
If elevations are provided on one component, it is preferred for at least one pole or at least one magnetization unit or at least one magnet or one coil to be provided on the other component. The number of magnetization units or poles can be 1 or else greater.
The shape of the elevations can fundamentally be arbitrary and can be semicircular, pointed or blunt, for example. The holding region of rotating bodies is preferably accordingly rounded.
One or more magnetization units or poles can be in the form of an electrical coil plus core or a permanent magnet or can consist of remanence material or a combination thereof.
The distances between individual elevations and/or magnetization units are preferably approximately uniform, but can also be arbitrary.
The depth, i.e. the radial extent or the axial extent, of individual elevations or magnetization units with respect to others can be different.
The field strength which is applied to or acts on the individual magnetization units can, in particular, also vary at the same time.
The speed of the rotating bodies does not have to be equal to the rolling speed, and can also deviate therefrom, for example by step-down or step-up transmissions. The inner part which is formed by the elevations, for example in the shape of a star, can be mounted off-center to the outer part.
Such a magnetorheological transmission apparatus can be used, for example, as a haptic knob with a latching pattern or in furniture and drawer guides with positions.
The magnet or each magnetization unit or the inner part and/or the outer part can also consist of remanence material.
Since magnetorheological fluids concatenate very rapidly upon the application of a magnetic field, it can be sufficient in the normal state, for example when driving an automobile, if the magnetic field is turned off. It is generally entirely sufficient to only turn on the field when a first rotational angle change is initiated. A significant amount of energy can thus be saved.
Alternatively, a base torque can be implemented with remanence. When a rotational angle change is registered, a dynamic magnetic field can be built up, which can also pulsate to generate a virtual latching pattern.
In configurations in which the remanence is utilized, the magnetic field for the remagnetization can be externally applied. A corresponding coil, which acts through a cylinder, for example, can be used for the remagnetization.
The method according to the invention is used to operate technical equipment and devices and, in particular, vehicles and particularly preferably motor vehicles, a haptic operating device having a rotating unit being used and selectable menu items being displayed on a display unit, and a menu item being selected or chosen by rotating the rotating unit. In particular, a torque profile is dynamically changed during rotation of the rotating unit and/or the rotating unit latches at a number of haptically perceptible latching points during rotation, the number of haptically perceptible latching points then being dynamically changed, in particular during operation.
The method according to the invention has many advantages since it enables simple and dynamically adapted operation. The individual menu items can be selected by rotating the rotating unit and can be clearly haptically distinguished from one another since a latching point or a stronger rotational resistance can be felt at each individual menu item. As a result of the dynamically changing number of haptically perceptible latching points during operation, the operation of the operating device can be optimally adapted to the respective requirements and to current operating states of the technical equipment or of the vehicle. Such a dynamically adapted procedure is therefore not possible with the haptic operating knobs from the prior art and is not known from the latter.
The latching points are preferably generated by deliberately generating a magnetic field at a channel at least partially filled with a magnetorheological medium. Such a channel extends, in particular, between a basic body and a rotating unit which is rotated in order to actuate the haptic operating device.
An angular position of the rotating unit is preferably detected, and an intensity of the magnetic field is set on the basis of the detected angular position. In this case, the angular position of the rotating unit can be recorded in absolute or relative terms.
In preferred configurations, an end stop is dynamically generated in at least one direction of rotation. The magnetic field is particularly preferably set to be considerably stronger at the end stop than at a latching point. As a result of such a dynamically set end stop, an end stop can fundamentally be provided at any desired angle position, with the result that the complete rotational angle does not need to be used to arrive at an end stop. As a result, after relatively small rotational angles, a user can also be easily made aware of the fact that yet further menu items are not provided during further rotation. An end stop can thus be dynamically generated, for example, after 2, 3 or 4 latching points.
A latching point is preferably generated at a determined angle position by virtue of a stronger magnetic field being generated there or in the vicinity of the latching point than further away from the latching point. For example, a stronger magnetic field can be generated at angular locations adjacent to the determined angle position than at the angle position determined for the latching point.
It is possible for the magnetic field to be intensified during a rotational movement away from the latching point, with the result that the user can clearly feel the latching point.
It is possible and preferred for a relative local minimum of the magnetic field to be generated at a latching point, whereas relative maxima of the magnetic field are generated in the immediate vicinity of the latching point. The magnetic field can be reduced again further away from the latching point. This means that the magnetic field is intensified at a distance of up to 25% of the distance between two latching points, for example, whereas it is set to be relatively small at a latching point itself.
In preferred configurations, the angular distance between at least two adjacent latching points is dynamically set. For example, the angular distance between two latching points may be respectively 10 or 15° for a number of 4, 6, 8 or 10 latching points, whereas the angular distance may be increased to 30°, for example, in the case of only 2 latching points. The relative angular distance can fundamentally be increased for a smaller number of latching points, whereas the angular distance is decreased for a larger number of latching points.
However, it is also possible for an angular distance between two latching points to be decreased—to a certain degree—if fewer latching points are provided. For example, a relatively small angular distance of 15° or the like can also be selected in the case of only 2 latching points and therefore 2 menu items, whereas the angular distance may be 30° if 4 menu items are selected or 4 corresponding latching points are dynamically generated. The latching pattern spacing may also always be the same.
In all configurations, it is preferred for the rotating unit to be endlessly and/or freely rotatable in the switched-off state. However, it is also possible for only a certain rotational angle of 150°, 180°, 360° or 720° or the like to be possible if, for example, there is a direct cable connection between a rotated part and a stationary part.
In all cases, it is also possible for a permanent magnet to ensure a certain base resistance during rotation in the switched-off state, for example. It is also possible to provide a mechanical or permanent-magnetic latching pattern for the switched-off state so that the user also receives haptic feedback in the switched-off state. In the case of a mechanical latching pattern, it is conceivable for the latter to be electronically compensated for in the normal operating state, with the result that, in the switched-off state, the user senses a mechanical latching pattern which is completely dynamically superimposed or replaced in the operating state.
In all configurations, it is preferred for the number of latching points to correspond to the number of currently available menu items. This means that, after selection of a menu item and appropriate guidance to a submenu, the number of then currently available latching points corresponds to the subitems in the then currently active submenu.
A selected menu item is preferably activated when the haptic operating device and/or the rotating unit is/are pressed. In all configurations, it is also possible and preferred for a touch-sensitive screen or a touch-sensitive display unit (for example capacitive, inductive etc.) to be used, in which a menu item can be selected by touching it with the finger or the like, for example. In all of these configurations, it is possible and preferred for both pressing of the haptic operating device and operation using the finger to be possible. This also applies to operation using gesture control. A gesture control sensor can be used additionally or instead of the screen for this purpose.
The display unit may be an LCD, TFT, IPS, Retina, Nova, White Magic, OLED, AMOLED or other screen type.
An associated method step is preferably carried out and/or an associated submenu is displayed and the number of latching points is dynamically adapted to the selectable menu items in the submenu when a menu item is activated.
A further method is used for operation or control in or of self-driving vehicles having an adaptive haptic operating device, the available menu items and the latching points of the operating device being adapted on the basis of an operating or driving state.
In this case, in particular, only those menu items or functions which are permissible based on the operating or driving state (in particular self-driving or are driven) can be selected and executed. Menu items and/or functions which possibly result in danger or are confusing are preferably hidden or deactivated.
Another method is used, in particular, for assisting with the rehabilitation of persons after illnesses, a haptic operating device being used. In this case, a variable rotational resistance is generated. In this case, the operating device can be used to open a door, turn a switch etc. The latching pattern and the force can be adapted in an infinitely variable manner.
In all variants, the haptic operating device has an infinite number of possible positions or latching patterns, in particular.
The combination of a touch display (display unit) plus a haptic operating device (haptic knob) can be used in a wide variety of applications. The same basic configuration (hardware) can be “adapted” by means of different software. For example, the operating device can be used in the washing machine as a rotating controller with coarse latching patterns (delicates, low-temperature, prewash etc.), and can be used in a baking oven with an infinitely variable, but increasingly difficult latching pattern for the purpose of adjusting the temperature. In all devices, the user therefore has a “known/identical” user interface but nevertheless product-specific user interfaces. The manufacturer hereby has more common parts, which makes everything more cost-effective.
Modern cameras have a large number of dials and operating knobs. Depending on the program selected, corresponding fine adjustments (for example aperture stops etc. in this case) can be changed by means of the haptic rotating unit (rotary knob) by pressing on the display (or a knob). Adapted latching patterns or latching points can be used for aperture stops and programs. A zoom can be operated in an infinitely variable manner with a central position at a focal length of 50 mm and with stops at the end of the zoom. The actuation force may possibly be increased shortly before the end stop.
These cameras may also be controlled using a mobile telephone or the like. An operating device according to the invention is also advantageous here.
The haptic operating device may also be the program selection element at one time and then the adjusting element for the zoom, each with different latching patterns.
The haptic latching pattern may also be installed in the objective in the multifunction rotating ring of the housing (multifunction ring in the cameras). The latching pattern changes depending on the use of the ring (zoom, aperture stops, shutter speed etc.).
In order to save space, weight and costs, the entire ring need not be in the form of an MRF ring in this case, but rather may be controlled via a small haptic element according to the present invention which is located to the side and is operatively connected via toothing or the like.
Persons with impaired eyesight can be assisted by corresponding feedback from the haptic operating element, for example in the form of a Morse code.
A room thermostat knob can indicate, for example, what temperature is being regulated. One pulse is one degree warmer, two short successive pulses are two degrees warmer. The temperature can be reduced if rotated in the other direction. The same applies to ovens, baking ovens etc.
Braille is even virtually possible using the haptic operating device. The torque profile against the rotational angle (rotation of the haptic knob) results in a Morse code or braille.
Furthermore, the dialing of a number can be described as follows:
digits are equal to the number of haptic pulses.
Following a stroke or similarly severe illnesses/events, persons must relearn many functions. The opening of a door or door lock, the turning of a switch, for example of the washing machine, writing etc. must be learnt and trained again. An ideal tool for this is available with the adaptive haptic operating device. The latching pattern and the force or the torque can be adapted in an infinitely variable manner and a training program is therefore possible. This applies not only as trainers for the hand but also many more (joints, fingers, legs etc.).
The method according to the invention is particularly preferably carried out using an apparatus according to the invention, thus resulting in a particularly advantageous method of operation.
Not only data relevant to the situation can be displayed and adjusted on the display unit, but other data, for example the time, SMS, the telephone book, can also be displayed.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a haptic operating device and method, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.